declare
T=
tree(key:a val:111
 left:tree(key:b val:55
       left:tree(key:x val:100
             left:tree(key:z val:56 left:leaf right:leaf)
             right:tree(key:w val:23 left:leaf right:leaf))
       right:tree(key:y val:105 left:leaf
             right:tree(key:r val:77 left:leaf right:leaf)))
 right:tree(key:c val:123
       left:tree(key:d val:119
             left:tree(key:g val:44 left:leaf right:leaf)
             right:tree(key:h val:50
                   left:tree(key:i val:5 left:leaf right:leaf)
                   right:tree(key:j val:6 left:leaf right:leaf)))
       right:tree(key:e val:133 left:leaf right:leaf)))
